Barometric instrument



June 7, 1949.

Filed Sept. 12, 1945 c. J. ULRICH BAnoMmR-IC NSTRUMENT s'heets-Sheet l June 7, 1949.

c. J. ULRICHv BAROMETRIC INSTRUMENT 2 Sheds-Sheet 2 Filed sept. 12, 1945 Patented June 7, 1949 UNITED STATE ENT OFFICE 9 Claims.

This invention relates to a scientific or laboratory instrument comprising a member having a heavy liquid such as mercury therein and tubes connected to said member adapted to contain atmosphere or another gas. Said instrument may comprise a barometer or a device for demonstrating certain laws of gases, such as Boyles law or Charles law. Such instruments usually comprise a member having a Ichamber with heavy liquid such as mercury therein with means for reducing the volume of said chamber to cause movement of saidmercury. One form of such a member used comprises a diaphragm with means for moving the same to cause movement of said mercury. Such prior instruments have been found very faulty in operation. Where a diaphragm is used, the same loses its resiliency and after the instrument has been used for .some time it is very difficult to adjust the same.

It is an object of this invention to provide a simple, efficient and easily operated structure for su-ch an instrument.

It is a further object of the invention to provide such lan instrument as above set forth in which a tube of resilient material such as rubber is used to contain the heavy liquid or mercury, together with means for compressing portions of said tube to cause movement of said liquid or l'fleICuIy.

It is still further an object of the invention to provide such an instrument comprising a tube of resilient material such as rubber having upwardly extending spaced portions connected at their lower ends, a heavy liquid such as mercury in said tube, rigid tubes such as glass tubes connected to the upper ends of said portions, together with adjustable means for compressing said resilient tube to cause movement of the mercury therein.

It is more specifically an object of the invention to provide a device comprising a tube of resilient material, preferably of U-shape, a body of heavy liquid such as mercury in said tube, rigid tubes such as glass tubes connected to the upper ends of said resilient tube, a rigid block having a groove in which said resilient tube is disposed, a member adjacent said block having projecting means thereon alined with said groove, and means such as a screw with a convenient handle thereon for moving said member toward said block to compress said resilient tube and cause movement of the mercury therein.

These and other objects and advantages of the invention will be fully set forth in the following description made in connection with the accompanying drawings in which like reference characters refer to similar parts throughout the several views and in which:

Fig. 1 is a view in front elevation of one form of the device;

Fig. 2 is a view in front elevation with certain parts removed;

Fig. 3 is a horizontal section taken on line A-B of Fig. 1;

Fig. 4 is a horizontal section taken on line C-D of Fig. 1;

Fig. 5 is a horizontal section taken on line E-F of Fig. 1;

Fig. 6 is a view in front elevation of a diferent form of instrument; and

Fig. 7 is a view in front elevation of still another form of instrument.

Referring to the drawings, particularly Figs. l. to 5, an instrument is shown comprising a supporting lmember IIJ. Said member H3, as shown in Figs. 1 and 2, is of elongated form, the same having rounded upper and lower ends and the same is substantially rectangular in transverse cross section. On its front side member l0 is provided with a pair of grooves lila, which grooves are joined at their lower ends by a semi-circular portion I 0b. A tube l2 is provided, which tube is substantially of U-shape, the same having upwardly extending parallel portions which are connected at their lower ends by a semi-circular portion. Tube I'2 is disposed in the slots Ilia and the connecting portion lll-b thereof. Tube i2 will be made of some resilient material such as rubber or a rubber composition. A rigid tube I3, which preferably will be made of glass, has its lower end received in one of the upper ends of tube l2 and this tube I3 extends upwardly to adjacent the top of member l2 and is also disposed in one of the grooves Illa, as shown in Fig. 3. Tube i3 will have a closed upper end. A scale I4 is formed on member le adjacent the upper end of tube i3 and the same is provided with graduations which will be provided with appropriate designations such as numerals indicating inches of mercury, as shown in Fig. 1. Another rigid tube i5 is secured in the upper end of the other part of tube l2 and extends upwardly a short distance therefrom. Tube I'5 will also preferably be made of glass and the same is disposed in the other groove Sila. Tube i5 will be open at its upper end. Tubes I3 and l5 can very conveniently be inserted in the ends of the resilient tube l2 and may also be securedy therein by some adhesive. Tubes i3 and l5 are held in place on member ifi by a transversely extending clamping member or cleat IS secured to member I by the spaced screws I l. Tube I 3 is further secured to member it by a small cleat I9 secured to member I' by spaced screws 2l. A member IB is disposed adjacent the front of member III at its lower end, the same having a ange I8a which extends along the sides of member Ill as well as around the lower end thereof. Member I 8 is thus in front elevation of the same general shape as the lower end of member I9. Member I8 has formed thereon a pair of projections or ribs I 8b which extend downwardly and are connected at their lower ends by a semi-circular portion so that they aline with and can move into the grooves Ia and portion IIIb thereof. A block 20, which preferably will be made of metal, is tted into member I0. at the rear side thereof, the same having a flange 26a through which attaching screws 24 pass. A screw 23 is threaded into block 20, the same extending through an opening I'8c in member I3 and also extending through a portion of member I0. Screw 23 is provided with a handle 25 shown as in the form of a small hand- Wheel, which preferably will have a knurled periphery. Wheel 25 has a reduced portion 25a having a surface adjacent member I 8 and adapted to engage member I8.

The tube I2 will contain some heavy liquid such as mercury. The device shown in Figs. 1 to forms a barometer. Member I0 is provided with a graduation or zero mark 26. When a reading is to be taken handle will be turned to move screw 23 and adjust the pressure of member I3 against tube I2 to bring the mercury therein just up to the zero mark 26. It will be seen that when wheel 25 is turned to move member I8 against tube I2 that the mercury in tube I2 will be caused to move upwardly into tubes I3 and I5. When wheel 25is turned sol that member I8 can move away from tube I2, said tube will tend to expand to itsv normal or fully expanded condition and the mercury will drop in tubes I3 and I5. When the mercury has been adjusted so that it is at the zeroI mark 26 in tube I5, a barometric reading 'can then be made on scale I I.

In Fig. 6 the invention is embodied in a device which is used for illustrating Boyles law. In this structure a base member 30 is used which will preferably be in the form of a tripod having lugs 39a at the ends of its legs through which supporting screws 3I are threaded, the same being provided with adjusting wheel-like. heads or handles 3| a. Member 30 has a central hub 3012 which is bored to have ft therein a stem 32a of a supporting member 32. Supporting member 32 will otherwise be identical with member IU already described except that the grooves 32h formed therein corresponding to grooves Illa will extend upward to the upper end thereof, which upper end extends atA right angles to the sides of member 32 instead of being rounded as is the upper end of member I0. Tubes 33 and 34, which will preferably be made of glass. are secured to the upper ends of tube I2 which will be provided, as shown in Figs. l to 5, and these tubes are disposed in the. grooves. 32h and extend to the top of member 32. Tubes 33 and 34 are held in place on member 32 by the cleat I6 already described, and a cleat 3G,` extending over said tubes and secured to member 32 by spaced screws 31. A scale 38 is formed on member I0 between tubes 33 and 34 having a zero mark disposed substantially at the top of member I6, said scale, being numbered in units often upward from said zero mark. A member 40 is slidable on member 32 and over tubes 33 and 34, the same having a transverse mark or small member such as a ne wire or hair 4I extending transversely thereof and substantially centrally vertically thereof. The top of the tube 34 will be closed and the top of tube 33 will be open.

As before stated, tube I2 will contain a heavy liquid such as mercury. Boyles law is broadly to the eifect that the volume of a gas varies inversely as the pressure. In using the instrument shown in Fig. 6, hand wheel 25 will be turned to move member I8 until the mercury in both tubes 33 and 34 is at the Zero mark on the scale 3B. Hand wheel 25 will then be turned to move member I8 toward member I0 to compress tube I2 and force the mercury upwardly in tubes 33 and 34. Member 4U can then be moved so that the mark 4I is at the top of the mercury in the tubes and the height of the mercury in each tube can be read. The reading in the tube 34 will indicate the volume of the gas in the upper end of said tube and the reading in the tube 33 will indicate the pressure. It lcan then be shown that the volume varies inversely as the pressure.

In Fig. 7 invention is shown embodied in another form of instrument which may be used to demonstrate Charles law. This instrument is identical with the one shown in Fig. 6 as far as the parts including member 32 are concerned. Tube I2 is used, as already described, and glass tubes 43 and 44 are secured in the upper ends thereof and disposed in the grooves 3217. A casing 4B, illustrated as of cylindrical form is provided, and the same has a supporting lug 4l secured thereto as by spaced screws 48. The lug 4l is apertured to have extend therethrough a supporting rod or standard 49 which will be connected at its lower end in any suitable manner to base member or tripod 30. The position of casing 43 on rod 49 canbe varied and said casing held in the desired position by a headed screw 49 threaded into lug -41 and engaging rod 49. Casing 45 has a cylindrical chamber therein and inlet and outlet pipes 5I and 52 respectively are secured to casing 46 adjacent the top and bottom thereof and communicate with said chamber. A rigid tube 54 which preferably will be made of glass, is Secured to the upper end of tube 44 by some simple connection such as the rubber tube 55. Tube 54 extends through the side of casing 45 and is connected to a smaller casing 5l which will be made of rigid metallic material such as copper. Casing 5l has a drain tube 51a at its lower end which. will be provided with some simple form. of closing clamp 58. Casing 46 has an opening at its upper end extending through a spout 46a and a thermometer 6I) will extend through said opening and into the chamber in casing 46 and. will be sealed in said casing. Member 40 is provided, as already described, in connection with Fig. 6, and the scale 38 will also be provided, as described in connection with Fig. 6. The top of tube 43 will be open.

The instrument shown in Fig. 7 is used to il lustrate Charles law or that the pressure of the gas varies as the absolute temperature or that with a fixed volume of gas the pressure decreases with a fall in temperature and increases with a rise in temperature. The tube I2 will contain mercury, as already described. The mercury will be adjusted to stand at a certain point in the tube 44, such as mark 6I. This will be done with the apparatus at room temperature, which temperature will be recorded. lThe height of the mercury I in tube 43 will be read and recorded. The chamber in casing 46 will` now bev lled with small pieces of ice and the temperature of casing v51 and the gas therein will be brought substantially to the freezing point. It will be seen that the gas in casing l is in communication with tube 44 and hence in communication with the mercury in tube l2. The gas in casing 51 was initially at room temperature and when it falls to freezing temperature its volume will diminish and the mercury will rise in tube 44. The mercury will now again be adjusted in tube 44 to bring it into register with mark El. This can bedone by rotating hand-wheel in a counter-clockwise direction thus relieving pressure on tube I2. When the mercury has again been brought to register with the mark 6I, another reading will be taken on tube 4'3 and this will be recorded. The chamber in casing will now be filled with steam. The steam can be admitted to said chamber through the spout or pipe 52 and can pass from said chamber through the spout or pipe 5I. When the chamber in casing 46 has been iilled with live steam, the temperature of the gas in casing 51 will be brought to 2l2 degrees F. or to the boiling point. The volume of the gas in casing 5l will thus increase. The increased volume of gas will cause the gas to pass into tube ist and the height of the mercury in tube 44 will be lowered. The mercury will now again be adjusted by turning hand-wheel 25 in a clockwise direction and compressing tube i2. mercury will thus be forced to rise in tube M and it will be brought to position to register with mark til. When the mercury is thus stationary at mark Si another reading on tube 43 is taken. rihe height of the mercury in tube A3 will show the pressure of the gas. Since the upper end of tube i3 is open, the pressure indicated by the mercury therein will of course have the pressure of the atmosphere added thereto. The various readings taken with the temperature of the gas in casing 5l at different temperatures will show that as the temperature of the ixed volume oi rises the pressure also rises. There will always be a fixed volume of gas in casing 5l and tube 5ft when the mercury is stationary at the point Si. The law that the pressure decreases with a decrease in temperature and rises with an increase in pressure can thus be nicely demonstrated.

From the above description it will be seen that I have provided a simple, eilcient and easily operated structure of instrument which can be used as a barometer or to demonstrate certain laws of gases. The resilient tube l2 is very easily procured and the compression and variation 4made in the same is easily done and the operation is very successful. Connections to the tube can be easily made and the glass tubes can be readily removed when desired. A very fine and accurate control can be had on the mercury by compressing tube I2 to reduce or increase the volume of the chamber therein. Several very troublesome objections encountered in previous structures of similar instruments have been overcome. The device, as stated, is quite simple, can be easily and inexpensively made and, as stated, very easily operated. The instruments have been amply demonstrated by actual use in laboratories and have been found to be very successful and efficient.

t will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the parts, without departing from the scope of applicants invention, which generally stated, consists in a device The 6l Y capable of `carrying out the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.

What is claimed is:

l. An instrument dealing with gases having in combination, a tube of resilient material having substantially parallel upwardly extending portions, said portions being connected at their lower ends, a heavy liquid in said tube, a rigid transparent tube connected to one end of one of said portions and extending upwardly therefrom, a second rigid transparent tube connected to the other of said portions and extending upwardly therefrom, a. member having parts adapted to engage said portions of said iirst mentioned tube at one side thereof rigid stationary means at the opposite sides of said portions, and means for moving said member toward said portions and stationary means for compressing the same and causing said liquid to rise in said portions.

2. A device of the class described having in combination, a U-shaped tube of resilient material having the spaced portions thereof extending substantially vertically, a heavy liquid in said tube, transparent tubes secured in the upper ends of said portions respectively and communicating respectively therewith, a rigid member having a groove in which said first mentioned tube is disposed, a second rigid member having ribs thereon transversely alined with said groove and adapted to engage said tube, and means for relatively moving said members to move said ribs against said tube and cause the liquid in said tube to move upwardly therein.

3. An apparatus of the class described having in combination, a tube of resilient material having spaced upwardly extending portions, said portions being connected at their lower ends, a body oi mercury in said tube, rigid transparent tubes secured in said portions respectively and communicating therewith, a rigid biock having grooves in which said portions are disposed, a member movable toward said block having portions adapted to engage said portions of said rst mentioned tube, and means for moving said member toward said block to compress said portions of said rst mentioned tube and cause said mercury to rise therein.

4. An apparatus of the class described having in combination, a tube of resilient material having spaced upwardly extending portions, said portions being connected at their lower ends, a body of mercury in said tube, a rigid transparent tube secured in each of said portions respectively and communicating therewith, and means for compressing said rst mentioned tube for causing the mercury to rise therein.

5. A resilient tube having spaced upwardly extending portions, said portions being connected at their lower ends, a body of mercury in said tube, a rigid block having a groove therein in which said tube is' disposed, a member at one side of said block having a rib thereon alined with said groove and adapted to move thereinto, and a rotatable member for moving said member toward said block to compress said tube and cause said mercury to rise therein.

6. An apparatus of the class described having in combination, an elongated member substantially rectangular in transverse cross section having a pair of spaced grooves formed in one face thereof and connected at their lower ends, a tube of resilient material disposed in the lower portion of said grooves, a body of mercury in said tube, transparent tubes secured to said rst mentioned tube and extending `upwardly vin said grooves respectively, Vmeans for holding said transparent tubes :in place, 4'a vsecond member adjacentl the lower end of said rst mentionedmember having a portion alined with the lower` portion of said grooves and Awith said rst mentioned tube and rotatable im'eans for :moving said second member toward said rst mentioned member and tube to compress 'said rst mentioned tube.

`i7. Aniapparatus of the class described having in combination, a U-'shaped tube of resilient material lfhaving its spaced portions extending upwardly, ,a body of mercury in said tube, a member having .a groove formed in one side thereof in whichsaid tube is disposed and supported, ftransparent tubes connected :respectively to said portions Yand communicating therewith, a second member vadjacent the side of said rst mentioned member having a rib thereon alined with said groove, :a nut Asecured to said rst mentioned member, a screw passing through said second member and .threaded in said nut engaging said second member, `and a vhandle on said screw vfor turning the same, moving said second member and .compressing said Aiirst mentioned tube.

:'8. A device :of the class -described having in combination, a `U-shaped tube of resilient material having upwardly extending spaced portions, a `:heavy liquid in said tube, rigid transparent tubes secured in the upper ends of said `portions respectively and respectively communicating therewith, a member on which said rst mentioned 'tube is fmounted, Ya -second member having parts adapted to engage the said portions and 8 means vfor relatively moving said 'members to compress said viirst `mentioned tube and cause said :liquid to rise in said portions and Ain said transparent tubes.

19. An apparatus of the class described having in combination, la member of 'resilient material having upwardly extending spaced portions, said member 4havlngfa, 'chamber therein extending into said portions, Va body 'of liquid mercury in said chamber, spaced transparent tubes 'secured to said portions and extending upwardly therefrom and coaxial Itherewith and communicating with said chamber, one `of said tubes having an open upper end and :the-other of said-tubes being much longer than said one tube and having a closed upper end, a lgraduated scale extending along said other tube, andmeans for compressing said member to cause -said 'mercury to rise in said tubes.

CARL J. ULRICH.

REFERENCES CITED `The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,815,000 Durant July 14, 1931 1,917,846 Klopsteg July 11, 1933 FOREIGN PATENTS Number Country Date 20,451 Germany Jan. 18, 1883 

